Question

我如何找到矩阵中是否可用的索引号？像

将numpy导入为np

R= np.matrix ([1,2,34,4,5,5,6,9], 
              [1,2,34,4,5,5,6,9],
              [1,2,34,4,5,5,6,9])

我要在这里搜索我的输入索引是否在“ R”中

Here my input index is C[4,4]

我想确定C [4,4]索引是否可用，然后他返回True，否则返回False 请帮我找到我的东西。

Answer 1

您只需检查矩阵的尺寸即可。...*** Test Cases *** Only upper limit [Documentation] Loops over values from 0 to 9 :FOR ${index} IN RANGE 10 \ Log ${index}

Answer 2

您的矩阵定义缺少[ .... ]。

您可以使用Ask for forgiveness not permission方法，也可以测试给定的索引是否不超过矩阵的形状：

import numpy as np

R = np.matrix ([             # missing [
    [1,2,34,4,5,5,6,9], 
    [1,2,34,4,5,5,6,9],
    [1,2,34,4,5,5,6,9]
])                           # missing ]

print( R.shape )  # (3,8)



def indexAvailable(M,a,b):
    # ask forgiveness not permission by simply accessing it
    # when testing for if its ok to access this    
    try:
        p = M[a,b]
    except:
        return False
    return True

print(99,22,indexAvailable(R,99,22))
print(9,2,indexAvailable(R,9,2))
print(2,2,indexAvailable(R,2,2))

输出：

99 22 False
9 2 False
2 2 True

或者您可以对照矩阵的形状检查所有给定的索引：

def indexOk(M,*kwargs):
    """Test if all arguments of kwargs must be 0 <= value < value in M.shape"""
    try: 
        return len(kwargs) == len(M.shape) and all(
            0 <= x < M.shape[i] for i,x in enumerate(kwargs))
    except:
        return False

print(indexOk(R,1,1))    # ok
print(indexOk(R,1,1,1))  # too many dims
print(indexOk(R,3,7))    # first too high
print(indexOk(R,2,8))    # last too high
print(indexOk(R,2,7))    # ok

输出：

True
False
False
False
True

如何查找输入索引是否在Matrix中可用或在python中不可用

2 个答案: